Burns

BURNS Myrna D.C. San Pedro, MD, FPPS

Definition Burns are a result of the effects of thermal injury on the skin and other tissues Human skin can tolerate temperatures up to 42-44 0 C (107-111 0 F) but above these, the higher the temperature the more severe the tissue destruction Below 45 0 C (113 0 F), resulting changes are reversible but >45 0 C, protein damage exceeds the capacity of the cell to repair

Classification According to Depth First-degree Burns (mild) : epidermis Pain, erythema & slight swelling, no blisters Tissue damage usually minimal, no scarring Pain resolves in 48-72 hours Superficial Second-degree Burns : entire epidermis & variable dermis Vesicles and blisters characteristic Extremely painful due to exposed nerve endings Heal in 7-14 days if without infection Midlevel to Deep Second-degree Burns : Few dermal appendages left There are some fluid & metabolic effects Full-thickness or Third-Degree : entire epidermis and dermis, no residual epidermis Painless, extensive fluid & metabolic deficits Heal only by wound contraction, if small, or if big, by skin grafting or coverage by a skin flap

Burn Photos Mild Burn 2 nd degree Burn 1 hr 2 nd degree Burn 1 day 2 nd degree Burn 2 days

Classification According to Extent Mild : 10% Moderate : 10-30% Severe : > 30% Hospitalization for > 10% of body surface area Infant Rule of Nines (for quick assessment of total body surface area affected by burns) 1% Perineum 9% Each Arm 14% Each Leg 18% Posterior Torso 18% Anterior Torso 18% Head Surface area Anatomic structure

Kinds of Burns Scald Burn : most frequent in home injuries; hot water, liquids and foods are most common causes; above 65 o C, cell death Flame Burn : due to gasoline, kerosene, liquified petroleum gas (LPG) or burning houses Chemical Burn : common in industries and laboratories but may also occur at home; acid is more common than alkali Electrical Burn : worse than the other types; with entrance and exit wounds; may stop the heart and depress the respiratory center; may cause thrombosis and cataracts Radiation Burn : from X-ray, radioactive radiation and nuclear bomb explosions

Burn Photos Scald Burns Flame Burns

Burn Photos Chemical (Acid) Burns Radiation (Flash) Burns

Burn Photos Electrical Burns Entrance Wounds Electrical Burns Exit Wounds Entrance wound of electrical burns from an overheated tool Severe swelling peaks 24-72 hrs after Electrical burns mummified 1 st 2 fingers later removed

U.S. Statistics About 2.4 million people suffer burns annually Account for an estimated 700,000 ER visits per year and 45,000 require hospitalizations Between 8,000-12,000 burn patients die, and approximately one million will sustain substantial or permanent disabilities Fires kill about 500 children < 14 years annually and injure 40,000 others Fire ranks 5th among accidental injuries, after motor accidents, poisoning, falls and drowning The majority of children < 4 years hospitalized for burn-related injuries suffer from scald burns (65%) or contact burns (20%)

Review of PGH Cases Period from January 1, 2000 to February 28, 2002 revealed 205 cases of pediatric burns Majority of pediatric burn injuries occur at home affecting children <5 years with mean age of 5.35 years old The risk of pediatric burn injury is inversely proportional to socioeconomic status Less common burn forms are from fires, firecrackers, explosions and electric shock

Physiological Response Typically, biphasic response The initial period of hypofunction manifests as: (a) Hypotension, (b) Low cardiac output, (c) Metabolic acidosis, (d) Ileus, (e) Hypoventilation, (f) Hyperglycemia, (g) Low oxygen consumption and (h) Inability to thermoregulate This ebb phase occurs usually in the first 24 hours and responds to fluid resuscitation The flow phase, resuscitation , follows and is characterized by gradual increases in (a) Cardiac output, (b) Heart rate, (c) Oxygen consumption and (d) Supranormal increases of temperature This hypermetabolic hyperdynamic response peaks in 10-14 days after the injury after which condition slowly recedes to normal as the burn wounds heal naturally or surgically closed by applying skin grafting

Pathologic Features Zone of coagulation (necrosis): Superficial area of coagulation necrosis and cell death on exposure to temperatures >45 0 (primary injury) Zone of stasis (vascular thrombosis): Local capillary circulation is sluggish, depending on the adequacy of the resuscitation, can either remain viable or proceed to cell death (secondary injury) Zone of hyperemia (increased capillary permeability)

Burn Pathophysiology: Edema Injured tissue  Increased permeability of entire vascular tree  loss of water, electrolytes and proteins from the vascular compartment  severe hemoconcentration Protein leakage  resultant hypoproteinemia, increased osmotic pressure in the interstitial space Decreased cell membrane potential cause inward shift of Na + and H 2 O  cellular swelling In the injured skin, effect maximal 30 min after the burn but capillary integrity not restored until 8-12 hours after, usually resolved by 3-5 days In non-injured tissues, only mild and transient leaks even for burns >40% BSA

Burn Pathophysiology: Cardiac Cardiac output decreases due to: Decreased preload induced by fluid shifts Increased systemic vascular resistance caused by both hypovolemia and systemic catecholamine release A myocardial depressant factor has been described that impairs cardiac function Cardiac output normal within 12-18 hours, with successful resuscitation After 24 hours, it may increase up to 2 ½ times the normal and remain elevated until several months after the burn is closed

Burn Pathophysiology: Blood The red-cell mass decreases due to direct losses Immediate, 1-2 hours after, and delayed, 2-7 days postburn, hemolysis occurs due to damaged cells and increased fragility Anemia within 4-7 days is common and expected, typically, will persist until wound healing occur; depressed erythropoietin levels documented Early mild thrombocytopenia (sequestration) followed by thrombocytosis (2-4x normal) and elevated fibrinogen, factor V and factor VIII levels commonly by end of the 1 st week A “normal” platelet or fibrinogen level may be an early sign of disseminated intravascular coagulation Persistent thrombocytopenia is associated with poor prognosis -- suspect sepsis

Burn Pathophysiology: Metabolic Severe catabolism with breakdown of muscle protein for gluconeogenesis as acute response Prostaglandins and cytokines implicated in increased core temperature of 1-2 0 C and in initiating acceleration of nitrogen catabolism Plasma levels of catecholamines, glucagon and cortisol all increase, maximal in patients with 50-60% TBSAB, while insulin and thyroid hormone levels decrease Hypermetabolic response may approach 200% of BMR remaining elevated for months after burn closed Early enteral feeding associated with lessening of the hypermetabolic response

Burn Pathophysiology: Renal Renal blood flow and GFR decrease soon after due to hypovolemia, decreased cardiac output, and elevated systemic vascular  oliguria and antidiuresis develops during 1 st 12-24 hours Followed by a usually modest diuresis as the capillary leaks seal, plasma volume normalizes, and cardiac output increases after successful resuscitation and coinciding with onset of the postburn hypermetabolic state, and hyperdynamic circulation

Burn Pathophysiology: Immunologic Mechanical barrier to infection is impaired because of skin destruction Immunoglobulin levels decreased as part of general leak and leukocyte chemotaxis, phagocytosis, and cytotoxic activity impaired The reticuloendothelial system's depressed bacterial clearance is due to decreases in opsonic function These changes, together with a non-perfused, bacterially-colonized eschar overlying a wound full of proteinaceous fluid, put the patient in a significant risk for infection

First Aid Measures in Burns Extinguish flames by rolling in the ground, cover child with blanket, coat or carpet After determining airway is patent, remove smoldering clothes and constricting accessories during edema phase in the 1 st 24-72 hours after Brush off remaining chemical if powdered or solid then wash or irrigate abundantly with water Cover burn wounds with clean, dry sheet and apply cold (not iced) wet compresses to small injuries; significant burns (>15-20% BSA) decreases body temperature which contraindicates use of cold compress dressings If burn caused by hot tar, mineral oil to remove it

Outpatient Management For 1 st and 2 nd degree burns less than 10% BSA Blisters should be left intact and dressed with silver sulfadiazine cream Dressings should be changed daily washing with lukewarm water to remove any cream left

Recommendations for Hospitalization Total burns >10% BSA or >2% full thickness, halved for <2 or >40 yr Hands, face, feet or genitalia involved Evidence or suspicion of inhalation injury Associated injuries present Suspicion that burn inflicted Burn is infected Burn circumferential History of prior medical illness Patient is comatose Patient or family unable to cope with situation

Hospital Management General assessment and cardiopulmonary stabilization Resuscitation Establishment of IV lines and blood studies Wound care and infection control Pain relief and psychological support Nutritional support Physical Therapy/Occupational Therapy

Airway compromise? Respiratory distress? Circulatory compromise? Intubation, 100% O 2 IV access, fluids Multiple trauma? Yes No Evaluate & treat injuries Burns >15% or complicated burns? Yes No Burn care, tetanus prophylaxis, analgesia IV access; fluid replacement Circumferential full thickness burns? Escharotomy Yes Yes No No

Initial Procedures Fluid infusion must be started immediately NGT insertion to prevent gastric dilatation, vomiting and aspiration Urinary catheter to measure urine output Weight important and has to be taken daily Local treatment delayed till respiratory distress and shock controlled Hematocrit and bacterial cultures necessary

Fluid Resuscitation For most, Parkland formula a suitable starting guide (4 ml Ringer’s Lactate/kg body weight/% BSA burned), ½ to be given over 1 st 8 hr from time of onset while remaining over the next 16 hr During 2 nd 24 hr, ½ of 1 st day fluid requirement to be infused as D 5 LR Oral supplementation may start 48 hr after as homogenized milk or soy-based products given by bolus or constant infusion via NGT Albumin 5% may be used to maintain serum albumin levels at 2 g/dl Packed RBC recommended if hematocrit falls below 24% (Hgb <8 g/dl) Sodium supplementation may be needed if burns greater than 20% BSA

Inhalation Injury Three syndromes: Early CO poisoning, airway obstruction & pulmonary edema major concerns ARDS usually at 24-48 hrs or much later Pneumonia and pulmonary emboli as late complications (days to weeks) Assessment: Observation (swelling or carbonaceous material in nasal passages Laboratory determination of carboxyhemoglobin and ABGs Treatment: Maintain patent airway by early ET intubation, adequate ventilation and oxygenation Aggressive pulmonary toilet and chest physiotherapy

Infection Control Tetanus prophylaxis : 250-500 IU TIG or 3000 units equine ATS ANST IM; Toxoid also Antibiotic of choice is one that will include Pseudomonas in its spectrum; most frequent pathogens in burns are Staphylococcus aureus, Pseudomonas aeruginosa and the Klebsiella-Enterobacter species Topical therapy : 0.5% Silver nitrate dressing Mafenide acetate or Sulfacetamide acetate cream Silver sulfadiazine cream Povidone-iodine ointment Gentamicin cream or ointment

Pain Relief and Adjustment Important to provide adequate analgesia, anxiolytics and psychological support to: Reduce early metabolic stress Decrease potential for posttraumatic stress syndrome Allow future stabilization and rehabilitation Family support patient through grieving process and help accept long-term changes in appearance

Nutritional Support Shriners Burn Institute at Galveston, Texas Guidelines for Caloric Intake 1500 kcal/m 2 BSA burned + 1500 kcal/m 2 total BSA Adolescents 1300 kcal/m 2 BSA burned + 1800 kcal/m 2 total BSA 2-15 years 1000 kcal/m 2 BSA burned + 2100 kcal/m 2 total BSA Infants

Complications of Burns Burn Shock Pulmonary complications due to inhalation injury Acute Renal Failure Infections and Sepsis Curling’s ulcer in large burns over 30% usually after 9 th day Extensive and disabling scarring Psychological trauma Cancer called Marjolin’s ulcer, may take 21 years to develop

Only those who will risk going too far, can possibly find out how far one can go. -- T. S. Elliott Thank You!

Burns

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